先查询一下是否存在产品
Dim dt1 As DataTable = DataTables("成品入库")
For Each p1 As String In dt1.GetValues("成品名称")
Dim dr1 As DataRow = DataTables("成品库存").Find("成品名称='" & p1 & "'")
If dr1 Is Nothing Then
dr1 = DataTables("成品库存").AddNew
dr1("成品名称") = p1
End If
dr1("入库总数") = dt1.Compute("sum(入库数量)","[成品名称] = '" & P1 & "'")
Next